An improved ventilator monitor and alarm system is to be developed which uses the Respitrace Inductive Plethysmography principle to quantitate actual tidal volume and minute ventilation in patients who are chronically ventilator dependent. Alveolar hypoventilation or overinflation of the patient can be detected if ventilation deviates from preset limits. Respiration will be monitored by a real-time microprocessor-based instrument and alarm system which will be calibrated for each patient and ventilator. The initial prototype shall be completed and patient evaluation begun during Phase I of funding. Potential advantages of this system include a higher degree of warning of ventilator malfunction or disconnection due to true monitoring of patient respiration, potential for long-term data logging of ventilation changes which may reflect a circadian rhythm and/or vary with changes of lung mechanics or disease, assessment of feasibility of weaning patients off ventilators and increased reliability of proper ventilator performance in home care environments with potential cost saving in attendant home nursing care personnel. Future validation of this technique might lead to the development of clinical or improved home apnea alarms for neonates, patients with central or obstructive sleep apneas, or apnea monitors for post-operative or intensive-care unit patients in hospitals.